short-acting insulin reduction strategies for continuous cycle ergometer exercises in patients with type 1 diabetes mellitus

Background: the fear of hypoglycemia is the strongest barrier when patients with type 1 diabetes mellitus consider physical ac- tivity. there is still a lack of information regarding pre- and post-exercise therapy adaptation strategies with respect to different exercise intensities corresponding to the three phases of lactate metabolism. objectives: the aim of this experimental, cross-sectional study was to investigate exercise intensity-dependent, short-acting insulin reductions to avoid hypoglycemia, applying standardized exercises using insulin degludec (®tresiba/novo nordisk, denmark). methods: seven male participants with type 1 diabetes mellitus were switched to insulin degludec. intensities for the 30 minutes continuous cycle ergometer exercise tests were set at 5% below (a) and above (b) the lactate turn point 1, and below (c) and above (d) the lactate turn point 2. reductions in short-acting insulin were applied as following: by 25% for intensity a, by 50% for intensity b and by 75% for intensities c and d four hours before the start of exercise and immediately after exercise. blood glucose, interstitial glucose, lactate, catecholamines, cortisol, igf-1 and glucagon were measured. results: no hypoglycemic events occurred, but linear blood glucose decreases were observed: 2.01 ± 1.04 mmol.l^-1 , p = 0.35 (a), 3.00 ± 1.54 mmol.l^-1 , p = 0.48 (b), 3.42 ± 2.34 mmol.l^-1 , p = 0.40 (c), and 3.70 ± 3.36 mmol.l^-1 , p = 0.12 (d). adrenaline, noradrenaline and igf-1 (b, c, d, not a), dopamine (c, d, not a and b) and cortisol (a, c, d, not b) increased significantly from baseline, but not glucagon (p > 0.05). interstitial glucose showed no post-exercise hypoglycemia. conclusions: the applied therapy adaptation before and after exercises was adequate to avoid hypoglycemia while using an ultra-long-acting insulin.